Twenty-five burned investors have asked to speak at the Manhattan federal court hearing where Bernard Madoff is expected to plead guilty Thursday in his $50 billion Ponzi scheme.

Neither the contents of the e-mails nor the senders were revealed, but prosecutors said the largest number of them, 27, dealt with “sentencing and forfeiture issues.”

Although crime victims generally speak only at sentencings, the 2004 federal Justice for All Act guarantees them “the right to be reasonably heard at any public proceeding . . . involving release, plea, sentencing or any parole proceeding.”

One of Judge Denny Chin’s clerks said yesterday, “It’s possible that he’s going to let people speak. It hasn’t been decided.”

Madoff, 70, currently faces a single count of securities fraud, which carries a maximum 20-year prison term and a fine equal to twice the money lost by his victims.